1. Field of the Invention
The present invention relates generally to the fields of microbial fermentation and cementitious admixtures. More particularly, it concerns the use of fermentation residues to improve the properties of concretes and similar products.
2. Description of Related Art
Fermentation is a well-known technique for producing a number of commercially relevant organic compounds, including, but not limited to, ethanol and organic acids. In fermentation, a microorganism, in many cases yeast, is grown in a fermentation vessel on a medium suitable for the microorganism""s growth. A commonly-used medium for yeast comprises dextrose and corn steep liquor. During the course of fermentation, the microorganism biomass increases and a commercially relevant target product is generated. After microorganism growth is complete, the target product is isolated, typically by one or more of distillation, crystallization, solvent extraction, and chromatographic separation. After recovery of the target product the microorganism biomass, non-fermentable components of the medium, and water-soluble compounds generated by the microorganism remain in the fermentation vessel. These components together may be referred to as xe2x80x9cbeer still bottomsxe2x80x9d or xe2x80x9cfermentation still bottoms.xe2x80x9d
To dispose of beer still bottoms, producers frequently pass this material to the animal feeds industry. This does capture some economic value from the material; however, this value is typically very low. Therefore, producers would prefer to capture more economic value from beer still bottoms than is possible from animal feeds uses.
Concrete is a ubiquitous construction material, both in the United States and in most countries of the world. In the United States during the year 2000, roughly 440 million cubic yards of ready-mix concrete were produced. In order to save on the amount of water used, enhance the properties of the concrete prepared therefrom, or both, about 90% of all ready-mix concrete in the United States is treated with an admixture. Low range water reducing admixtures are often used at about 0.25 gal per cubic yard. High range water reducing admixtures are often used at about 1 gal per cubic yard. Assuming that these admixtures are produced as solutions comprising 50 wt % solids, annual admixture demand in the United States alone would be in the range of 50 million pounds to 100 million pounds.
Therefore, it would be desirable to have a new and valuable use for beer still bottoms or one or more components thereof. It would also be desirable to have cementitious compositions with improved flow and related properties without a concomitant increase in the amount of water required in the cementitious composition. It is well known in the art that increased water in the cementitious slurry will decrease the ultimate strength of the hardened material.
Yoshizawa et al., U.S. Pat. No. 4,311,721, reports the extracting of water-soluble compounds from fermentation still bottoms and the use of the water-soluble compounds in a fermentation medium or an animal feed.
Willgohs, U.S. Pat. No. 5,662,810, discloses the use of dewatered beer still bottoms as an animal feed.
Hamstra et al., U.S. Pat. No. 5,760,078, teaches the extraction of potassium salts from the water-soluble compounds of fermentation still bottoms, and the use of such potassium salts as a fertilizer.
Sapienza, U.S. Pat. No. 6,315,919, reports the use of water-soluble compounds from beer still bottoms as a deicing agent.
In one embodiment, the present invention relates to a composition comprising a cementitious material and a fermentation residue.
In another embodiment, the present invention relates to a method of preparing a composition comprising a cementitious material and a fermentation residue, the method comprising (i) growing a microorganism on a medium, to form at least a microorganism biomass and fermentation residue; (ii) separating the fermentation residue from the microorganism biomass; and (iii) combining the fermentation residue with the cementitious material, to form the composition.
In still another embodiment, the present invention relates to a method of producing a cementitious structure, comprising (i) combining at least a fermentation residue, a cementitious material, and water, to yield a slurry; (ii) forming the slurry into an unset cementitious structure; and (iii) setting the unset cementitious structure, to yield the cementitious structure.
In a further embodiment, the present invention relates to a composition, comprising a fermentation residue, water, and an inorganic material dispersed in the water.
In yet a further embodiment, the present invention relates to a method of preparing a composition comprising a fermentation residue, water, and an inorganic material dispersed in the water, the method comprising: (i) growing a microorganism on a medium, to form at least a microorganism biomass and fermentation residue; (ii) separating the fermentation residue from the microorganism biomass; and (iii) combining the fermentation residue with the water and the inorganic material, to form the composition.
In still a further embodiment, the present invention relates to a method of producing a paper structure containing an inorganic material, comprising: (i) combining a fermentation residue with water and an inorganic material, to yield a solution; (ii) treating the paper structure with the solution, to yield a treated paper structure; and (iii) removing water from the treated paper structure, to yield the paper structure containing the organic material.
The various embodiments of the present invention provide a new and valuable use for fermentation residues. The present invention also provides for cementitious compositions with improved flow and related properties without a concomitant increase in the amount of water required in the cementitious composition.